Multiple-fuse plug.



LFELDKAI\/1P,J. P. PAYOR 62 H. PAYSON.

MULTIPLE FUSE PLUG.-

APPLICATION man .lAN.18| 1915.

1,27 ,256. Patented May 22, 1917.

av F v W 15 T" W ATTORNEYS UNITED STATES PATENT OFFICE.

FREDERICK A. FELDKAMP, OF NEWARK, NEW JERSEY, JOSEPH P. PAYOR, OF NEW YORK, N. Y., AND HAROLD PAYSON,

OF SHORT HILLS, NEW JERSEY, ASSIGNORS TO THE SIX-IN -ONE FUSE COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YOR Specification of Letters Patent.

MULTIPLE-FUSE PLUG.

Patented May 22, 1917.

Application filed January 18, 1916. Serial No. 72,681.

ber axially movable and preferably rotatable with respect thereto, one member carrying the fuse elements and the other carrying a selective switch or contact adapted to close a circuit through the different fuse-elements by the rotation of the rotatable member, bringing the selective contact into circuit with one or another of the fuse elements.

In such fuse plugs it is possible, while the plug is in circuit, to draw an are at the individual fuse contacts by inexperienced persons slowly moving the switch member either axially, or, when axial movement is not provided for, by shifting or rotating the switch member to bring the different fuse contacts in circuit. This arcing burns or roughens the switch contact and also heats the fuse contacts and fuses, thus affecting and altering their capacity or rating and poss bly destroying them. It also makes it possible for the arc to be blown out between the ad acent surfaces of the plug members and burn the operator. Both the possible changes in rating of fuses and the possibllity of danger to inexperienced persons tampering with the same, are important factors in the use of fuse plugs, and these troubles have made it extremely diflicult to manufacture satisfactory multiple fuse plugs except n very small current capacities, and the difficulty hasbeen increased due to the limited space available per fuse where a number are employed in one 1 P O fie of the objects of this invention is to provide a fuse plug of this general character having provisio for obviating these difiiculties.

In the preferred form of the invention, this is accomplished by maintaining the cir-.

cuit at the fuse contacts. until it'is broken elsewhere at a safe point, preferably within someinclosed part of the plug or socket by the movement of the switch member. In the preferred form of the invention, means is provided for causing the movable member to be moved axially a definite distance to insure the opening'of the circuit at the inner point before the member is shifted or rotated to open the contact at the fuse.

Further objects and advantages of the in? vention will more fully appear from the following description taken in connection with the accompanying drawings illustrating the preferred embodiment of the invention.- l

The invention consists in the novel arrangement, construction and combination of parts hereinafter described in their preferred form and more particularly pointed out in the appended claims.

In the drawings, Figure 1 shows a sectional elevation of a fuse plug (in a socket) embodying the preferred form of the invention;

Fig. 2 shows a cross-sectional view taken on line 22;

Fig. 3 shows a plan view of the bottom of the upper member; and

Fig. 4 shows a reduced-elevation of one of the plug members.

Referring to the drawings, 1 is a fuse plug having a base member 2 and an upper relatively movable switch member 3 shown in the form of a cap superimposed concentrically on the base member and axially and rotatably movable with respect thereto, as hereinafter described. The base member is fitted with a threaded shell plug contact 4: adapted to fit a threaded socket shell contact 5, and it is also provided with a central plug contact member 6 having a contacting head 7 adapted to engage the socket contact 8. This central contact member extends freely through a central recess 9 formed in the base member, this recess housing a spring 10 abutting at one end against a shoulder 11 near the end of the recess, and at the other end pressing against the inner surface of the contacting head so as to normally force. the central contact member down in engagement with the socket contact 8. The upper end of the central contact member extends into the upper plug member 3, and to its upper end is rigidly secured a 'spider in place. .'Individual recesses or chambers 15 reach from the annular cham- [ber for housing the fuse elements, these individual chambers having a restricted opening at their bottom communicating with individual recesses or chambers 16 which taper downwardly and outwardly ;to receive tapering or cone-shaped fuse contacts 17 to which the free ends of thefuse elements are connected. The lower end of the upper or cap plug member is also recessed or chambered to form an annular chamber for receiving and inclosing the upper end of the base plug member, and it is provided centrally with a tapering recess 18 adapted to receive a taperingprojection 19 from the base member, thus constituting a tapering interlock for centering the two plug members, tending to hold them in alinement during the relative axial movement between them, thus constituting in, a way guides to maintain the proper alinement of the two members and thus take this strain from the other coacting and interlocking parts. For the purpose of more securely fastening the central contact member 6 in the upper plug member 3, and for strengthening the edges of the central interlocking parts of the two plugs, the contact member 6 is provided with a washer 20 rigidly secured thereto.

The individual fuse contacts 17 are arranged concentrically around the central plug contact member 6, these contacts being disposed so as to be successively engaged by a selective switch or contact member 21 having a tapered contacting head 22, the

switch member being slidably mounted in a .recess 23 formed in the base plug-member containing a compression/spring 2 1 tending to thrust the selective contact upward into engagement with the fuse contacts. This selective switch member is connected at its lower end by means of a flexiblepig-tail or other suitable connection 25, to the contact shell 4. The upward movement of the switch member, due to the action of the spring, is limited by any suitable means,

' such as by a pin 25 or the pig-tail which extends into an opening in the lower part of the switch member. of the plug is preferablymade of porcelain, while the upper member is preferably made of some less refractory substance, such as a suitable asphaltum compound. After the electric-a1 parts and the springs have all been The lower member assembled in place, the upper annular chamher is filled in with a suitable sealing compound, such as plaster of Paris 26, or the like, and if desired, a suitable name-plate 27 placed thereover. The spring 24 operating the selective contact is designed to move the contact upward a certain distance as the upper or cap plug member is lifted, so as to maintain contact between the fuse contacifand this member until after the circuit is broken at some other and safer point, such as within the socket .and plug at contacts and 8 in the form of the invention .shownfsince these last two contacts will be rangement of the selective and fuse contacts are such that they in themselves constitute interlocking parts between the two plug members to prevent rotation until after the upper member has been lifted the desired distance to break the circuit at contacts 7 and 8; But in order to relieve these parts of the shearing strain that would be caused by an attempt to rotate the upper part before it was lifted clear of the selective contact, we provide, in the form of the invention shown, other interlocking parts which hold the two plug members from relative rotation until the upper'member is lifted a safe distance to break contact at 7 and 8 and to also lift the upper member clear of the selective contact. These interlocking parts (Figs. 3 and 4) consist of projections 28 extending upwardly from the lower member and engaging recesses29 inthe upper member. In the present form of the invention, there are three projections in the base member and six recesses in the u per member for determining the position 9 the upper member relative to the lowermember, so as to bring the fuse contacts in proper, alinement with the selective contact. The projections 28 are partly offset from the rim of the lower member, and the receiving sockets are partly formed in the rim of the upper plug member, as shown in the drawings.

The chambers 15 may be filled with the socket; the operator simply takes hold of the upper; plug member lifting it until the interlocking projections are clear, and then rotates it, at the same time releasing his up- I ward pull, and the selective contact will thereupon snap into the next fuse contact it reaches.

If anyone should idly play with the plu while in circuit, they will first have to li the cap member axially, whereupon the cirerator or apparatus.

cuit will be broken down in the plug and socket Where it will do no harm to the op- Furthermore, no harm to the electrical contacting interlocking parts can be done by rotating the upper member, because the interlocking parts. 28 and 29 take all shearing strain off of these. It will further be observed that the two parts of the plug are permanently but resiliently held together by the central contact member and the spring 10, and that they cannot be separated intentionally or unintentionally without destroying the plug; so that none of the parts can be lost to render the plug useless,

While we have shown the fuse elements carried in the upper plug member and permanently connected to the central contact member, and have shown the central contact member breaking circuit at its lower end, it will be obvious to those skilled in the art, after understanding our invention, that changes may be made in these and variousother features of our invention without. departing from the scope and spirit of the same, and we do not wish to be understood as limiting ourselves other than as indicated in the appended claims. J Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is

1. In a device of the *character described, the combination of two plug members, one a base member having a shell plug contact and also having a central opening, a central plug contact member axially and rotatably movable in said central opening and having a contactingv part at its lower end, the other plug member being superimposed on the base member and secured to said central contact member to move axially and rotatably therewith, a spring engaging the base plug member and the central contact member for pressing the two plug members together, said plug memloers having interlocking parts requiring a predetermined axial movementbetween them to disengage the upper member for rotation, one of said plug members carrying a selective contact adjacent the other plug member and connected to one of the plug contact members, the other plug member carrying a plurality of separated and protected fuse elements connected at one end to the plug contact a member to which the selective conta'et is not connected, and at their other-ends having fuse contacts arranged about the central plugcontact member so as to be engaged by the selective contact vwhen the upper plug member is rotated, and a sprmg pressmg the selective contact into engagement with the fuse contact in (alinement therewith, whereby the circuit through the plug is maintained at the fuse contact until broken at the central contact member.

e5 2. In a device of the character described,

the combination of two plug members, one I a base member having a shell plug contact and also having a selective contact at its upper surface connected with said shell contact, said base member also having a central opening, a central plug contact member axially and rotatably movable in said central opening, the other plug member being superimposed on the base member and secured to said central contact member to move axially and rotatably therewith and having a plurality of fuse elements each, having contacts disposed around the central contact member in position to be engaged by the selective contact when the upper plug member is rotated, and each fuse element connected at its other end to the central plug contact member, the plug members having interlocking parts requiring axial movement between them to disengage the upper member for rotation, a springvengagfuse contact in alinement therewith, whereby the circuit through the plug is maintained at the fuse contact until broken at the central contact member so as to prevent arcing at the fuse contacts when the upper member is rotated.

3. In a device of the character described, the combination of two plug members, one a base member having a shell plug contact and a central plug contact member each adapted to engage a contact of a plug socket, the other plug member being rotatable and axially displaceable relative to the base member, the central plug contact member extending freely upwardly through the base member to the other plug member to which it is secured, a spring for normally holding said plug members togethr-r with the lower end of the central plug contact member in position to engage one of the socket contacts but permitting said central contact member to be lifted out of engagemeiit when the upper plug member is lifted, a plurality of fuse elements carried by one of said plug members and connected at one end to one of said plug contacts'and at their otherv end being provided with individual contacts spaced about the central contact member, a selective contact carried by the other plug member and connected to the plug contact to which the fuses are not con nected and adapted to engage serz'atim said fuse contacts when the rotatable member is rotated relative to the base member, the coning the base plug member and the central 'ally displaceable relatively to the other, the

the combination of two plug members, one a base member having a shell plug contact and a central plug contact member, the other plug member being rotatable and aXially displaceable relative to the base mem-- ber, the central contact member having a contacting part at which a circuit through the plug is opened by the axial movement of the movable plug member, one of said plug members having a plurality offuse elements each having one end arranged about the central contact member and'adjacent the other plug member, and said other plug member having a selective contact adapted to engage the different adjacent fuse ends when the movable plug member is rotated, the said circuit including the central plug contact member, a fuse, the selective contact in engagement therewith, and the shell plug contact, said circuit having means for maintaining it at the selective contact when the movable plug member is moved axially until the circuit is broken at the contacting part of the central contact member 5. In a device of the character described, the combination of two plug members, one a base member and the other a superimposed member, one being rotatable and axibase' member having two plug contacts adapted to engage socket contacts, one of said plug members having a plurality of fuse elements protected therein one from the other, means connecting said fuse elements at one end to one of the plug contacts, said fuse elements having contacts at their other ends arranged to be successively engaged by acontact on the other plug member when one member is rotated relatively to the other, a selective contact on the plug member not carrying the fuses, adapted to successively engage the fuse contacts when relative rotation is'produced, said conta t engagement being yieldable to permit some axial displacement of the plug members without breaking the contact, said selective contact being electrically connected to the other plug contact not connected to the fuses, the circuit from the socket contacts including a fuse, being adapted to'be first broken Within one of the plug members before it is broken at the yieldable contact, whereby arcing at the yieldable contact is prevented.

6. In a multiple fuse plug, the combination of two plug members one of which is provided with a plug shank for fitting plug sockets having socket contacts, the other plug member being rotatable with respect to the first member when the latter is inserted in a socket, a plurality off-uses carried by one of the plug members, a circuit for connecting one or another of the fuses to the socket contacts, said circuit including two contacts operated sequently by the movement of the movable plug member for breaking the circuit, one of said contacts being a selective fuse contact and the other being a contact actuated by the movement of said movable plug member for breaking the circuit before it is opened at the selective fuse contact.

7. In a multiple fuse plug, the combination of two plug members one of which is provided with a plug shank for fitting plug sockets having socket contacts, the other plug member being axially and rotatably, movable with respect to the first, a plurality of fuses carried by one of the plug members with fuse contacts arranged about the axis of rotation of said rotatable member, a circuit for connecting one or another of the fuses to the socket contacts, said circuit including an axial contact member in the form of a'spindle for the rotatable plug'member, and also includingtwo sequently operated contacts for making and breaking the circuit by the movement of the movable plug member, one of said sequently operated contacts being a selective fuse contact operatingto open the circuit after it has'been broken at the other contact.

8. In a multiple fuseiplug, the combination of two plug members one of which is provided with a shank for fitting plug sockets, said member having an outer shank contact for engaginga socket contact, the other plugmember being superimposed on top of the first and being provided with a plurality of fuses having contacts exposed toward the lower plug member to be engaged by a selective contact on said lower member, said selective contact having a spindle slidably mounted in the lower plug member and a spring cooperating therewith to force the selective contact upwardly to hold it yieldably in engagement with the adjacent fuse contact, and a central contact spindle secured to the upper member, to move therewith and extending slidably through the shank member and a fuses carried by one member, contacts secured to said fuses, a selective contact on the other plug member adapted to engage the different fuse contacts, means for connecting one end of the fuses to one of the socket contacts, means for connecting the selective contact to the other socket contact, and separate means for interlocking said members from relative rotation until they have been separated a definite distance axially, said means comprising a plurality of peripheral projections on one member and a plurality of recesses in the other member into Which the peripheral projections fit.

In testimony whereof, We have signed our 10 names to this specification.

FREDERICK A; FELDKAMP. JOSEPH P. PAYOR. HAROLD PAYSON. 

